Shankless bit holder and clamp



March 14, 1939. E. REANEY 2,150,561

SHANKLESS BIT HOLDER AND CLAMP Filed March 12, less if INVENTOR-Patented Mar. 14, 1939 UNITED STATES PATENT OFFICE SHANKLESS BIT HOLDERAND CLAMP Ernest Reaney, Stratford, Conn., assignor to The 0. K. ToolCompany, Inc., New York, N. Y., a corporation of New York ApplicationMarchl 12,

Claims.

5 ofi'set relation with the longitudinal axis or coincidental therewith.

A primary aim of the invention is to render available a holder in whichshankless bits may readily be inserted, adjusted laterally, or removed,and in which a firm and rigid seating of the bit is provided in anyposition of lateral adjustment within the range of the tool.

A further object of the invention is to obtain such firm and rigidclamping of the bit in a man-- 7 ner whereby the stresses incident tothe tooling operation that normally tend to overturn the bit or knock itfrom its seat in the holder, are transmitted directly to integrallyformed portions of the body member.

Still a further object of the invention is to attain a secure clampingof a shankless L-shaped bit byforces applied across the top of therearwardly extending portion and in a manner whereby the overturningforces are transmitted to the body member rather than to the clamp screwor other medium that initially effected the clamping action.

A further aim of the invention is to attain a firm clamping of tool bitsof the shankless type with a minimum of parts or mechanism and compactlyto arrange such parts entirely behind the upstanding portion of theL-shaped bit so as not to interfere with the work or freedom of chipremoval and in a manner capable of subsequent manipulation and use withrelative ease.

A further aim of the invention is to attain a firm clamping of ashankless bit in a recess at the end of a holder by forces actinggenerally downward and rearward in a direction substantially coincidentwith the direction of the forces reacting from the cutting operationthus relieving the clamping instrumentalities of counterstresses andpromoting a high degree of rigidity to the assembled tool. A clamp meansso designed will hold the bit against its lower and rear seatingsurfaces and simultaneously over its upper surface which in effect abutsagainst a rigid portion of the holder which overlies the bit. Theinitial clamping is effected by moving the bit in the same generaldirection that it is urged during actual cutting operation by forcesthat simultaneously clamp the bit between upper and lower portions ofthe holder body. With this construction the tool bit is positivelyrestrained from overturning 1938, Serial No. 195,472

and the initial clamping element relieved of the shocks and strainsincident to normal use.

In attaining the objectives of the invention it is proposed to use abody member having strong, tough characteristics, such as a forging, andto form therein a bit socket extending crosswise its forward end. Thelower surface of the socket is rearwardly and downwardly inclined, tofavorrearward movement of the bit under the action of the clamp meansand the tooling forces, and which terminates in an upstanding rearabutment surface coextensive in Width. A complementally shaped tool bit,inserted in the recess, may thus be adjusted laterally withoutrestriction.

To hold the bit in place it is proposed to extend a portion of theforged body member for- Ward into overlying relation with the tailportion of the bit but spaced therefrom a distance sufficient to permitthe use of an intervening rearwardly and downwardly movable clamp piece.To promote the clamping action the space between the overlying portionof the body and the tail portion of the bit is wedge shaped (in alongitudinal vertical section), the wedge being formed in part by aupwardly sloping surface of the bit and a downwardly sloping of theunder surface of the overlying portion of the body, and both surfacesare located to the rear of the upstanding portion of the bit.

A wedge block is interposed between the sloping surfaces and is arrangedto be pushed rearwardly and downwardly as by means of a set screw. Asthe wedge piece is moved rearwardly it tends to pull the tool bit in thesame direction, and as it moves downwardly, it tends to push the bit inthat direction, with the result that the bit is urged firmly against thebottom and rear walls of the socket and simultaneously clamped along itsupper surface. By this means a shankless tool bit may be clamped firmlyin its seat in the end of a holder with the assurance that the bit willnot be overturned or knocked out of its socket by reason of the clampscrew or the clamp element itself being cracked, bent, or forced out ofposition by a sudden downward blow at the end of the tool bit. In thepresent construction a portion of the solid body of the holder overliesthe bit and in the intervening space a wedge block is inserted whichtransmits such overturning forces directly to the body so that theclamping element itself is not required to withstand any force but thatof compression and the clamp screw relieved of substantially allstresses.

The actuating screw engages the wedge block preferably intermediate itsends, and to provide the necessary room for the screw, the wedge blockis enlarged in that region and a corresponding cavity is made in thebody member to receive it. This construction has the advantage that thewedging action and consequently, the clamping action is caused to occurmost strongly at the sides of the assembly where the greatest clampingforce is necessary. In prior constructions where a single screw or clampelement engaged the bit at a single point near its center, the clampingwas effected at a point some distance removed from the outer edges ofthe bit and holder, and in consequence, left those outer portionsunclamped and subject to yielding. Such disadvantages are entirelyeliminated by a'tool constructed in accordance with this inventionwherein the bit is clamped along its outer marginal edges.

Other objects and advantages will be in part indicated in the followingdescription and in part rendered apparent therefrom in connection withthe annexed drawing.

To enable others skilled in the art so fully to apprehend theunderlying'features hereof that they may embody the same in the variousways contemplated by this invention, a drawing depicting a preferredtypical construction has been annexed as a part of this disclosure and,in such drawing, like characters of reference denote corthereof.

Fig. 3 is a front view of the bit socket.

Fig. 4 is a side View detail of the bit clamp.

Fig. 5 is a vertical section through the clamp means. 7

Fig. 6 is a partial sectional view along lines 6- -6 of Fig. 5.

.The tool illustrated in Fig. 1 comprises an elongated body member IDhaving formed at its forward end a bit receiving recess I I within whicha tool bit I2 is adapted to be seated and clamped. The body Ill has aportion II! underlying the tool bit, and a portion Ill overlying thetool bit, and between the two portions a wedge block I3 and the bit I2are mounted. As shown more clearly in Figs. 2 and 4, the lower bitseating surface I4 is inclined rearwardly and terminates an upstandingabutment surface I5. Both surfaces extend crosswise the holder so thatthe tool bit may be inserted from either side and adjusted laterally tothe right or to the left.

The tool bit I2 is generally L-shaped in character and provides anupstanding cutting portion IZ and a rearwardly extending base and tailportion I2 The upstanding portion gives body and strength and providesmaterial for regrinding, and the base portion which has its lowerand endseating surfaces I2 and I 2 complemental to the cooperating surfaces ofthe bit socket, pro vides relatively wide and flat seating surfaces anda means for clamping. The'upper surface I2 of the tool bit'slopesforwardly relative to the bottom surface I2 so that the tool bit iswider at its rear end than at a point immediately adjacent theupstanding portion I2 The purpose for an enlarged end is to provide anabutment effective to resist inadvertent forward movement of the bitwhen clamped, and also to afford a semipositive abutment for urging thebit rearwardly anddownwardly during the manual operation of clamping thebit in its socket.

Inorder to efiect a firm clamping over relatively large areas orsurfaces of the bit without risking snapping or bending of the clampinginstrumentality, the portion "l of the body is formed to extend forwardas to overlie the tail portion of the bit. The under surface of theoverlying portion is disposed at a relatively wide, forwardly divergent,angle relative to the top surface I2 of the bit. Within the space I6thus formed, a wedge shaped compression member I3 is inserted. The lowersurface of the wedge engages the clamping surface l2 of the bit and theupper surfaces engages the sloping surface I! of the overhanging portionof the body.

The wedge member I3 is coextensive in width to the body member as shownin Fig. 3 and is provided intermediate its ends with screw clamp means-I 8. To receive the screw, the member I3 is enlarged as at I9, and acorresponding recess 20 is formed in the body to receive it. This methodof construction leaves two forwardly projecting portions 2| and 22 ofthe body member overlying the tool bit and bit seat, and two laterallyextending wedge portions 23 and 24 at opposite ends of the wedge;member, with an intermediate portion definitely interlocked andpositively preventing any side slip of the wedge relative to the body.The construction is such that during the clamping action the endportions of the wedge block have a firm bearing or backing directlyagainst portions 2| and 22 of the body. If desired, a slight clearancemay be provided between the center portion I9 and recess 20, and betweenthe clamp screw I8 and the wedge member I3 to simplify manufacture.

As illustrated in Figs. 4 and 5, the path of movement of the wedge blockis in a downward and rearward direction approximating the same directionas the resultant of the tooling forces acting at the front end of thebit. By reason of the gradual enlargement of the tail portion of thetail bit, movement of the wedge downwardly and rearwardly exerts asemi-positive force on the tool bit, thus also moving it downwardly andrearwardly until clamping is attained over the surfaces I4 and I5.

As previously mentioned the upper and lower sides of the wedge blockdiverge at a relatively wide angle. This is necessary in order to insurethe semi-positive pushing as well as pulling action in the tool bit, inelfecting clamping thereof on the three sides with due regard, ofcourse, to the slope of the lower seating surface I4. By making theincluded angle on the wedge piece approximately 30 and the includedangle of the tail portion of the bit approximately 10, a good clampingaction is obtained.

' The included angle of the wedge piece should, however, be greater thanthe angle of friction but less than 90 to obtain the best results withinthe space limitations in that particular region of tools of thischaracter. For example, if a very low angle is used, too great alongitudinal movement of the wedge piece is necessary to secure adequateclamping or free releasing for adjusting purposes and space limitationsin that particular region in holders for tool bits of this characterprohibit such large movements. Also, with a low angle diiiiculties inreleasing for regrinding and readjustment purposes are encountered. Ifan unduly wide angle is used the objectives of a three surface clampingwithout the risk of bending or breaking one or more of the clamp partsincident to the act of clamping or resulting from a sudden blow at theend of the tool bit, are defeated.

It' will further be seen that with the present invention the actualclamping-force is exerted toward the outer edges of the bit, so whetherthe assembly be used for cutting on the right or on the left, the bit isclamped on the side nearest the cutting action and also on the sideopposite where greater lever action is obtained. In this invention thedisadvantages found in earlier devices in which clamping was effected ata single central point and the outer margins of the bit left unclampedand subject to springing and yielding tendencies resulting in rockingeffects of the bit, have effectively been eliminated.

As is apparent from the foregoing, the strong and rigid clamping of thetool bit in the present invention, is effected in all positions oflateral adjustment within the range of the tool. And so that suchlateral adjustment may be effected in unit increments of definiteamounts, a series of interlocking formations are provided between theseating surfaces of the bit and holder. In Figs. 5 and 6, the formationsare indicated as serrations 25 and 26 extending downward and rearward inthe direction of the clamping movement of the bit. Hence, the serrationsserve as a guide during the clamping action and as positive means forpreventing twisting or pivoting of the bit on its seat.

Without further analysis, the foregoing will so fully reveal the gist ofthis invention that others can, by applying current knowledge, readilyadapt it for various utilizations by retaining one or more of thefeatures that, from the standpoint of the prior art, fairly constituteessential characteristics of either the generic or specific aspects ofthis invention and, therefore, such adaptations should be, and areintended to be, comprehended within the meaning and range of equivalencyof the following claims.

Having thus revealed this invention, I claim as new and desire to securethe following combinations and elements, or equivalents thereof, byLetters Patent of the United States:

1. A shankless tool bit and holder combining a body member having a bitreceiving recess across its forward end, said recess being defined by alower fiat bit seating surface and a rear abutment wall inclinedslightly forward as to overlie a portion of the seating surface, saidabutment wall being a plane surface coextensive in width with saidseating surface; a shankless tool bit having a lower and a rear surface,complemental to the said surfaces defining the recess, adapted to befitted in said recess, said bit having an upper clamp engaging surfaceinclined generally downward in a forward direction and extendingcrosswise the tool bit; a clamp element having a portion thereofengageable with said upper surface of the bit and an opposite portionengageable with the under surface of an overlying portion of the bodymember, said upper clamp surface of the bit and said under surface ofsaid overlying portion of the body member being disposed at an angle ofnot less than 25 converging rearwardly; and means for urging said clampelement rearwardly to effect a clamping of the bit upon said seatingsurface and simultaneously against said rear abutment wall.

2. A shankless tool bit and holder therefor combining a body memberhaving a bit receiving recess across its forward end, defined by a lowerfiat bit seating surface terminating in an upstanding rear abutmentsurface; a shankless tool bit having a lower surface and a rear surfacecomplemental to the surfaces defining the bit recess adapted to befitted in said recess, said bitalso having an upper clamp engagingsurface inclined generally downward and forward and extending crosswisethe tool bit; said body also having a portion thereof overlying saidrecess and spaced from the top of the inserted bit; a clamp element insaid space between said bit and the overlying portion of the body andhaving a portion thereof engageable with said upper surface of the bitand an opposite portion engageable with the under surface of theoverlying portion of the body member, said upper clamp surface of thebit and said under surface of said overlying portion of the body memberand the correspond-ing surfaces of said clamp element being disposed atan angle greater than the angle of friction but not exceeding 90 andconverging rearwardly; and means for urging said clamp elementrearwardly and downwardly to effect a clamping of the bit upon saidseating surface and simultaneously against said rear abutment wall.

3. A shankless tool bit and holder therefor combining a body memberhaving a bit receiving recess at its forward end, said recess beingdefined by a lower fiat bit seating surface and a rear abutment surface,said abutment surface being coextensive in width with said seatingsurface; a shankless L-shaped tool bit having a lower surface and a rearsurface complemental to the said surfaces defining the recess adapted tobe fitted in said recess, said L-shaped bit having an upper clampengaging surface extending crosswise the tool bit disposed to the rearof the upstanding portion thereof; said body member also having aportion overlying the rear portions of said bit and bit recess with itsunder surface disposed at an angle to the clamp surface of the insertedbit and spaced therefrom; a clamping wedge insertable in said space andhaving a portion thereof engageable with said upper surface of the bitand an opposite portion engageable with the under surface of saidoverlying portion of the body member, said wedge thereby transmittingdirectly to the body member the forces incident to the tooling operationtend ing to overturn said bit; interfitting means between said bit andbody member affording lateral adjustment of the bit relative thereto inpositive unit increments; and means for urging said clamping wedgerearwardly to effect a clamping of the bit upon said seating surface andsimultaneously against said rear abutment surface.

4. A shankless tool bit and holder combining a body member having a bitreceiving recess extending across its forward end, a shankless tool bitadapted to be fitted in said recess and laterally adjusted therein,saidbit having an upper clamp engaging surface extending crosswise thetool bit; said body also having two projecting portions overlying saidrecess and spaced from the said upper surface of the inserted bit; aclamp element in said space having a portion thereof engageable withsaid upper surface of the bit and two opposite portions respectivelyengageable with the under surface of the projecting portions of the bodymember, said upper clamp surface of the bit and said under surfaces ofsaid projecting portions of the body member being disposed at an angleof less than 90 and converging rearwardly; means for urging said clampelement rearwardly to effect a clamping of the bit upon said seatingsurface and simultaneously against said rear abutment wall; andinterlocking means between said clamp element and said body restrainingrelative lateral movement therebetween.

5. A shankless tool bit and holder therefore combining a body memberhaving a bit receiving recess at its forward end, said recess beingdefined by a lower flat bit seating surface and a rear abutment surface,said abutment surface being coextensive in width with said seatingsurface; a shankless L-shaped tool bit having lower and rear surfacescomplemental to the surfaces defining the recess adapted to be fitted insaid recess and to be adjusted laterally therein to various positions,said bit having at its rear an upper clamp engaging surface extendingcrosswise the tool bit; said body member also having a portion overlyingsaid bit and bit recess with its under surface disposed at a relativelywide angle to the clamp surface of the inserted bit and spacedtherefrom; a clamping wedge insertable in said space and having aportion thereof engageable with said upper surface of the bit and anopposite portion engageable with the under surface of said overlyingportion of the body member, whereby said wedge is caused to transmitdirectly to the body member the forces tending to overturn said bitincident to the tooling operation; and means for urging said clampingwedge downwardly and rearwardly toeifect a clamping of the bit upon saidseating surface and simultaneously against said rear abutment wall inany laterally adjusted position.

ERNEST REANEY.

